id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
18166	Allow the formset class to contribute kwargs to form instances	tevans	nobody	"When we use a formset, each form is instantiated by the method BaseFormSet._construct_forms(), which is called from BaseFormSet.__init__()

_construct_forms() allows for additional kwargs to be passed through to the individual form constructor, but BaseFormSet.__init__() does not provide any mechanism for kwargs to be passed through to the _construct_forms() call.

Also, we may not be able to supply a static unchanging list of kwargs that should be supplied to each form constructor - the kwargs we want to pass may depend upon the specific instance of the form being instantiated.

I propose the following changes:

Add a form_kwargs argument to BaseFormSet.__init__(). This would be stored on self, and consumed in BaseFormSet._construct_forms()

Add a method, BaseFormSet._kwargs_for_form(self, i). This method would be called for each form instantiated, passing the index of the form within the formset. The return value of this method would be merged with the form_kwargs supplied in BaseFormSet.__init__() and used to instantiate the form.

With these changes, a user could add additional constructor arguments to all forms by passing in form_kwargs to the formset constructor, and could add additional constructor arguments to specific forms by implementing _kwargs_for_form on a derived BaseFormSet class.

(I found it strange, when BaseFormSet was written, it was clearly intended to be able to pass kwargs to the forms - _construct_form() allows for it, there just is not the plumbing to do so. I worked around this by redefining - copy/pasting - the _construct_forms() method in my derived BaseFormSet class)

Patch doesn't have tests or doc changes, will add if this idea gets traction.

Cheers

Tom"	New feature	new	Forms	dev	Normal		forms formset kwargs		Unreviewed	1	0	0	0	0	0